Metal Halide Perovskite Nanocrystals for Near-Infrared Circularly Polarized Luminescence with High Photoluminescence Quantum Yield via Chiral Ligand Exchange

Abstract

Using ligand exchange on FAPbI₃ perovskite nanocrystals (PNCs) surface with chiral tridentate l-cysteine (l-cys) ligand, we successfully prepared chiral FAPbI₃ PNCs that show circularly polarized luminescence (CPL) (dissymmetry factor; <i>g</i>_lum = 2.1 × 10^-3) in the near-infrared (NIR) region from 700 to 850 nm and a photoluminescence quantum yield (PLQY) of 81%. The chiral characteristics of FAPbI₃ PNCs are ascribed to induction by chiral l/d-cys, and the high PLQY is attributed to the passivation of the PNCs defects with l-cys. Also, effective passivation of defects on the surface of FAPbI₃ PNCs by l-cys results in excellent stability toward atmospheric water and oxygen. The conductivity of the l-cys treated FAPbI₃ NC films is improved, which is attributed to the partial substitution of l-cys for the insulating long oleyl ligand. The CPL of the l-cys ligand treated FAPbI₃ PNCs film retains a <i>g</i>_lum of -2.7 × 10^-4. This study demonstrates a facile yet effective approach to generating chiral PNCs with CPL for NIR photonics applications.